Nogueira, Pedro, Rúben Aguiar, Rui Rodrigues, Eugénio Oliveira, and Lennart Nacke. “Fuzzy Affective Player Models: A Physiology-Based Hierarchical Clustering Method”. Proceedings of the AAAI Conference on Artificial Intelligence and Interactive Digital Entertainment 10, no. 1 (October 8, 2014): 132–138. Accessed May 21, 2026. https://ojs.aaai.org/index.php/AIIDE/article/view/12719.